Plate type evaporator for ice slabs



Jan. 25, 1966 F. SWANSON PLATE TYPE EVAPORATOR FOR ICE SLABS Filed NOV. 13, 1963 I/IIIIIII I INVENTOR.

J70 ncZZdFSwQnwm United States Patent 3,230,736 PLATE TYPE EVAPOR TOR FOR ICE SLABS Donald F. Swanson, St. Paul, Minn., assignor to Whirlpool Corporation, a corporation of Delaware Filed Nov. 13, 1963, Ser. No. 323,359 3 Claims. (Cl. 62-515) This invention relates to refrigeration apparatus in particular to ice maker apparatus.

In one form of ice maker apparatus, a slab of ice is formed on an evaporator plate over which water is flowed while the plate is concurrently refrigerated. Such slab forming plates are conventionally inclined slightly so that upon completion of the forming of the slab of ice, the slab may be slightly melted to permit it to slide downwardly from the slab onto a suitable means for cutting the slab into cubes as desired. An excellent example of such'a slab ice forming structure is shown in Ayres et al. United States Letters Patent 2,995,905.

. The present invention comprehends an improved slab and forming plate structure for use in such apparatus. Thus,

a principal feature of the present invention is the provision of a new and improved ice maker structure.

Another feature of the invention is the provision of such a structure arranged in a new and improved manner for providing facilitated ice slab formation.

A further feature of the invention is the provision of such a structure comprising a first wall formed of a material having a high thermal conductivity and defining a slab freezing surface and an opposite surface, a second wall formed of a material having a thermal conductivity lower than that of the first wall, the second wall having a first surface confronting the opposite surface of the first wall and defining therewith an evaporator passage, and means sealingly joining the walls.

Still another feature of the invention is the provision of such a structure wherein the wall defining the slab freezing surface is laminated.

Yet another feature of the invention is the provision of such a structure wherein the second wall further defines peripheral upstanding edge walls at the edges of the first wall.

Yet another feature of the invention is the provision of such a structure wherein means are provided for sealing the peripheral edge of the first wall to the second wall.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIGURE 1 is a perspective view of a slab ice maker provided with an evaporator structure embodying the invention;

FIGURE 2 is a perspective view of the evaporator structure;

FIGURE 3 is a fragmentary enlarged transverse section thereof taken substantially along the line 3-3 of FIGURE 2;

FIGURE 4 is a fragmentary transverse section similar to that of FIGURE 3 but illustrating a modified form of evaporator structure embodying the invention; and

FIGURE 5 is a fragmentary transverse section similar to that of FIGURE 3 but illustrating another modified form of evaporator structure embodying the invention.

In the exemplary embodiment of the invention as disclosed in FIGURES 1 through 3 of the drawing, a slab ice maker apparatus generally designated is shown to comprise an evaporator structure generally designated 11 over which a body of water W is flowed from a suitable distributor 12. The evaporator structure 11 is suitably refrigerated by means of refrigerant delivered thereto through a delivery conduit 13 to form a slab of ice which upon completion of the formation thereof is caused to pass downwardly from the evaporator structure 11 onto a cube forming apparatus generally designated 14 wherein the slab is cut into a plurality of cubes C. In the illustrated embodiment the cube forming apparatus comprises a plurality of heated grid wires 15 arranged in criss-cross fashion which by virtue of the heat generated therein slowly cut through the slab to form it into the plurality of cubes C which are then collected in a subjacent bin 16. As further shown in FIGURE 1, the water flowed over the evaporator structure 11 is collected in a trough 17 and delivered through a delivery conduit 18 to a sump 19 from which it is pumped by a suitable conventional pump 20 through a delivery conduit 21 to the distributor 12.

As indicated briefly above, the present invention is concerned with an improved construction of the evaporator structure 11 providing improved formation of the ice slab. More specifically, as shown in FIGURES 2 and 3, the evaporator structure 11 comprises a first flat wall 22 defining an upper slab freezing surface 23, side edges 24, rear edge 25, and a forward edge 26.

The first wall 22 is carried on a second wall generally' designated 27. The second wall includes a bottom portion 28 having a depressed serpentine portion 29. As best seen in FIGURE 3, the first wall 22 is facially juxtaposed to the bottom portion 28 of the second wall 27 whereby the depressed portion 29 defines with the first wall 22 an evaporator passage 30.

Second wall 27 further includes a pair of upstanding side wall portions 31 and an upstanding rear wall portion 32 defining a continuous U-shaped edge wall for guiding the water W from the delivery means 12 over the first wall 22 and over a first, downturned apron por tion 33 into the trough 17 as shown in FIGURE 1.

The wall 22 is preferably formed of a material hav ing a high thermal conductivity such as nickel. Referring to FIGURE 4, the slab freezing wall, illustrated in FIGURE 4 as wall 122, may be laminated to form a highly thermally-conductive wall. lllustratively, the wall 122 may comprise a laminate of stainless steel-copperstainless steel sheets, a laminate of stainless steel-aluminum-stainless steel sheets, a laminate of stainless steel-iron stainless steel sheets, and the like. The laminates may be formed by heating and rolling, or the respective sheets thereof may be joined by means of silver solder sheets disposed between the layers. Illustratively, the stainless steel sheets may be formed of a stainless steel having a high thermal conductivity and may be approximately .02 inch thick, the copper sheets may be approximately 0.25 to .030 inch thick, and the aluminum sheets may be .04 inch thick. In all other respects the evaporator structure 111 incorporating the laminated wall 122 is similar to and function similar to the evaporator structure 11.

The second wall 27 of the evaporator structure 11 is preferably formed of a material having a thermal conductivity lower than that of the first wall 22. Illustratively, the second wall may be formed of a stainless steel having a low thermal conductivity such as 302 stainless steel having a controlled amount of carbon.

In the illustrated embodiment of FIGURES 1 through 3, the walls 22 and 27 are seam welded along the edges of the passages 30. The edges 24 and 25 of the first wall 22 are preferably sealed to the second wall portions 31 and 32 by means of a joint 34 which may comprise a soldered, welded, epoxy cemented, or the like joint. Such a joint may be formed of a suitable solder such as -5 solder. Edge 26 may be similarly sealed to apron 33 by a solder joint as desired.

Thus, the evaporator structure 11 and evaporator structure 111 provide an improved slab forming structure wherein the slab forming surface is defined by a wall having a high thermal conductivity for facilitated'heat transfer between the refrigerant in the evaporator passages St) and the water W flowing over the upper surface 23. The evaporator structure may be formed in a simple and economical manner with the evaporator passages being defined by suitable embossing of the lower wall portion 280i the. second wall. The wall 22 may be rigidly secured to the. lower wall portion 28 of the second wall 27 by spot welding-between the passes of the passages 30 and by seam welding along the edges of the passages. Aseal between the walls at the edges of the upper wall 22 may be easily. effected by suitable soldering means. Thus, the evaporator structure is extremely simple and economical of construction while yet providing an improved facilitated iceslab formation.

Referring now to FIGURE 5, still another evaporator structure designatedzll embodying the invention is shown to comprise a structure generally similar to that of structure 111, but having atopwall 222 defined by an upper sheet 2-35 having extended edges defining the upstanding side walls 231, and end wall 232. The top wall 222. com- .prises a laminated structure wherein the sheets may be formed of material similar to the sheets of .wall 122. Thus, illustratively, the top wall '222 may comprise a laminate of stainless steel, copper, and stainless steel sheets, etc., as discusedrelative to wall 122. The lower wall 22'7 is similar to the lower wall 127 except that the edges thereof terminate subjacent the side walls 231 and end wall 232. The lower. wall 22? may be formed of a suitable material, such as stainless steel, having a thermal conductivity lower than the thermal conductivity of the top wall 222 wherein the stainlesssteel sheets may be formed of stainless steel having high thermal conductivity. In all other respects the evaporator structure 211 is similar to the evaporator structures 11 and 111.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes,'theref0re, in

the construction and arrangement may be made without departing from the, spirit and scope of the, invention as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An evaporator structure for forming a slab of ice, comprising: a first wall having a high thermal conductivity and defining a slab freezing surface and an opposite surface; a second wall having a first-surface. portion confronting said opposite surface of said first walland defining therewith an evaporator passage and a peripheral upstanding wall portion extending along the periphery of said first wall and defining the boundary of a slab freezing space overlying said slab freezing surface, said-first surface portion and said upstanding wall portion being formed of a single sheet of material having a thermal conductivity lower than that of said'first wall; and means sealingly joining said walls.

2. The evaporator structure of claim 1 wherein said first wall-is laminated.

3. An evaporator structure for forming a slab of ice, comprising: a first wall having a high thermal conductivity provided with a first surface portion defining .a slab freezing surface and an opposite surface portion; a second wall formed of a material-having a thermal conductivity lower than that of said first wall, said second wall having a first surface portion confronting .said-opposite-surface portion of said first wall and defining therewith an evaporator passage; and means sealingly joiningsaid walls, said first wall being laminatedandincluding an upper sheet defining upstanding edge walls. 1

References Cited by the-Examiner UNITED STATES PATENTS Ayres et al. 62 344 ROBERT A. OLEARY,Primary-Examiner. v 

1. AN EVAPORATOR STRUCTURE FOR FORMING A SLAB OF ICE, COMPRISING: A FIRST WALL HAVING A HIGH THERMAL CONDUCTIVITY AND DEFINING A SLAB FREEZING SURFACE AND AN OPPOSITE SURFACE; A SECOND WALL HAVING A FIRST SURFACE PORTION CONFRONTING SAID OPPOSITE SURFACE OF SAID FIRST WALL AND DEFINING THEREWITH AN EVAPORATOR PASSAGE AND A PERIPHERAL UPSTANDING WALL PORTION EXTENDING ALONG THE PERIPHERY OF SAID FIRST WALL AND DEFINING THE BOUNDARY OF A SLAB FREEZING SPACE OVERLYING SAID SLAB FREEZING SURFACE, SAID FIRST SURFACE PORTION AND SAID UPSTANDING WALL PORTION BEING FORMED OF A SINGLE SHEET OF MATERIAL HAVING A THERMAL CONDUCTIVITY LOWER THAN THAT OF SAID FIRST WALL; AND MEANS SEALINGLY JOINING SAID WALLS. 